@make[report] @device[X2700] @majorheading[Telefile] @section[General] Telefile is a small company (owned by a U.S. parent) producing a switch called TelePAC. This is a M68000-based switch using the standard VME bus. The basic system has 128 Kbytes of store (soon to be expanded to 2 Mbytes). It is claimed that 100 virtual calls can be supported. TelePAC units will be able to be joind together using a DMA interface. This interface could also be used to connect to a user-programmed processor supporting a UNIX- compatible system for use as a Gateway or other such protocol converter. STEEL Ltd., Livingston, now have the sole rights for sales in the Academic Community. @section[Hardware Description] The Telepac is based on the standard VME bus with an 8 MHz M68000 processor. A variety of card cages can be supplied which then dictates the maximum configuration for that particular switch. The software for the switch is supplied on ROMs, a card containing 64 Kbytes of battary backed RAM is used to contain the configuration and statistics. The current switch offering then adds further 64 Kbytes memory cards as desired. A 2 Mbyte memory board has been identified and will be offered in a standard switch shortly. The current model of the switch does not need or support any disc storage, a floppy disc is being as an option to allow more permanent storage for the configuration data and also to allow the switch to be dumped. An X.25 link is supported on an interface which contains the driver chips and clock source. Each pair of X.25 links are controlled by a DMA which contains a Moterola DMA chip that can handle 4 concurrent 'channels' into main memory. All of level 2 is handled by the 68000. @section[Software Description] The software for the switch has been written in M68000 assembler, there is a reasonable division between the various parts of the software. @section[Configuration Options] An X.25 line is plugged into an interface card, which comes in several types to support the different interfaces. Two interface cards are supported by a single DMA card. The size of card cage used determines the maximum number of lines, the smallest will take 5 DMA cards and hence supports 10 lines. A larger card cage is also on offer than can take up to 16 DMA cards and hence 32 lines. This cage is used to build standard configuration of 8, 12, 16 lines all of which can be expanded up to the maximum 32 lines. @section[Line Speeds/Interface Options] A maximum line speed of 153 Kb/s is supported. All lines on a switch may run at this speed. The interface options supported are: V24, V35 and X21. The interfaces are supported by using different Line Interface Cards and may be freely interchanged. In order to allow the V35 option to fit on the same size of card as the V24 option, a non-standard presentation is using a V24 style socket. The switch supports both internal and external timing, with internal clock rates of; 2.4, 4.8, 9.6, 19.2, 38.4, 76.8 and 153 Kb/s. @section[Throughput] A throughput of 581 data packets through the switch is claimed, this performance was observed while using a traffic generator by Telefile itself. The switch switch loaned to the ERCC achieved 400 data packets/sec, limited by the test equipment connected to only 8 lines. @section[Costs] @begin[verbatim] Model No. No of Lines Cost Comments --------- ----------- ---- -------- T3639-001S 10 @T{#}8,450 This unit has only 128K of store and is not expandable. T3639-101 8 @T{#}14,900 2 Mb of store expandable to 32 lines. T3639-102 12 @T{#}17,000 - do - T3639-103 16 @T{#}19,300 - do - @end[verbatim] It is noted that the 48 line system requires two boxes. In addition to the above, if a floppy disc is required, it will cost @T{#}1,860 A two part extension costs @T{#}1,300 (including interface modules) @begin[verbatim] - 18 @T{#}20,600 - 30 @T{#}27,000 - 48 @T{#}50,400 @end[verbatim] @section[X.25 Facilities] Fast Select, Packet and Window negotiation, PVCs and Reverse Charging are supported. Call Statistics are not currently supported but are targetted for the December release. Call Redirection is also targetted for the December release. The current Telepac software will repack packets containing more than 128 bytes into two 128 byte packets (using the more bit). This is a limitation caused by the current memory boards and will be removed when the 2 Mbyte boards are supplied. @section[Multinode Networks] Multinode networks can be supported using 'simple' X.25 to interconnect the switches. Any line can be a DTE or a DCE. It has been pointed out to Telefile that using this strategy means that Network Clearing codes are lost and they are investigating a further configuration option that would allow a connected DTE to pass in Network Clearing codes. @section[Addressing] An addressing table is held in the battery backed RAM and can be amended at any time without the need to reload the switch or even restart a line. The form of the addressing table is a Port name (actually the name of a logical channel - but in a simple configuration there need be no difference) and an X.25 address. If less than 12 digits is supplied as the address then a match is performed on the digits supplied. This allows ranges to be entered - but on a restricted form, ie. the range 7250 to 7275 could not supported, only 7200 to 7299. It is planned to strip off leading zeros in the December release of the software. Multiple entries for a single 'line' may be entered. It has been pointed out to Telefile that this scheme means that 1234 and 000000001234 would be different addresses and hence need multiple ???? in the routing table. The expansion of 1234 to the full digit address is now scheduled to be completed by ?. @section[Network Management] Modules exist within the switch to collect various network management statistics and to direct this information to the Network Management centre. The information is passed over a 'simple' X.29 call, ie. all the information is passed in a purely text form that could be dumped to a printer. In the current software this call MUST be made from outside the switch into the management module, thus preventing the use of a printer simply attached to a PAD. Telefile will offer a network management package, in December, designed to run on an IBM PC with the X.25 card produced by Forge. The cost of this software is @T{#} 1,000 per site. This software will also poll the switches for performance figures and error conditions. As with the statistics, this is achieved by transmitting the command in text as would be issued by the operator at the control console and analysing the text response from the switch. Between 30 and 40 can be controlled from this terminal, or if desired, the software could be implemented in a user's host machine. @section[Statistics] The current software only counts the number of calls, data packets and CRC errors but Telefile have stated that the rest will be added in the December release of the software. The switch complies with the rest of the points in the specification. @section[Operator Control] It is not yet possible to disable a link, although it has been stated that this is planned for January 1986. The status of a link can be determined. It is not possible to clear down a particular logical channel. Network addresses can be changed without restarting the line whose address is being altered. The change of line speed requires the line interface card to be removed and plugs changed but this can be done on a live system with no problems. The current software does not have password control on remote access to the control functions of a switch although Telefile have promised to add this feature in the december release. One restriction is that only one 'operator' may be active at any one time. @section[Date-Time STamp] Messages are date and time stamped. The date and time is held in battery backed RAM Compatibility, and is not lost when the power supply fails or the system crashes. @section[PSS Capability] Telefile has stated that they are prepared to guarantee compatibility with PSS. @section[Performance - Packet Transmission] @begin[verbatim] Call Requests 47.0ms Data Packets 6.2ms Clear Request 16.8ms @end[verbatim] @section[Availability and Reliability] It is estimated that the mean time between failure for hardware reasons is about 6000 hours. Telefile will be prepared to guarantee a MTBF of 2000 hours for all reasons. @section[Operation] The system is currently loaded from ROM and the configuration from battery backed RAM. No dumping is currently performed but this will be available on systems that include a floppy disc. @section[Reconfiguration] The reconfiguration tools are extremely flexible, although the current documentation needs upgrading in order to make it more obvious which of the available options should be used to create a switch that performs as expected in the Community environment. @section[Known Problems] There a number of points of variance with the JNT spec but Telefile have agreed to change their software to match the requirements either by the December or January releases of the software. A number of problems have already been resolved since a switch was loaned to the ERCC. @section[X.25 (1984)] Telefile are prepared to upgrade the switch to ISO DP8878 when requested by a customer. This could be made a requirement of the first few procurements. @section[Academic Community Special Requirements] By early 1986, it will be possible to link up Telefile switches by parallel channel interfaces. ONe potentially useful option would be to mount the conversion aids in a separate M68000 processor linked in such a fashion. @section[Product History] The current switch has been on the marked for about 3 1/2 years but has not been marketed as an X.26 switch to any extent. Approximately 100 systems have been installed worldwide, including 30 in the USA and Canada. @section[Company Information] (Details of size and size of parent in USA - Check) @section[Contact Name] @flushleft[R. Chisholm, STEEL Ltd., 3 Young Square, Brucefield Industrial Park, Livingstone, EH54 9BJ. Tel. No. 0506 411503.] @section[Confidentiality] None. @section[Summary]